The present invention broadly relates to fittings or faucets or appliances and, more specifically, pertains to a new and improved construction of a sanitary fitting.
Generally speaking, the sanitary fitting of the present development is of the type comprising a control cartridge which is arranged in a fitting housing or body, is actuatable from a lateral end of the fitting housing, and is connected at the inlet side thereof with at least one supply or feed line, the control cartridge serving to regulate water flowing through the fitting to an outlet. The fitting also comprises a safety device which is likewise provided in the fitting housing and arranged downstream of the control cartridge, viewed with respect to the predetermined direction of flow, the safety device serving to prevent a backflow of water into the aforementioned at least one supply or feed line. The safety device comprises a ventilation aperture which is closed in the presence of normal water flow and which, under conditions rendering possible a backflow of water, is open for ventilating at least the outflow line or conduit connecting the safety device with the outlet.
There are heretofore known sanitary fittings in which a back or return suction of dirty or contaminated water into the supply or feed line can endanger the quality of feed-water. Such appliances can be particularly washbasin fittings and sink fittings comprising a pull-out hose shower or sprayer, as well as shower and tub mixing faucets and combination sets including a hose shower. In such fittings it can occur that the shower is left lying in a washbasin or tub when, for example, the water supply or feed line is cut off or interrupted. If at such a moment the control cartridge of the sanitary fitting is open, the washbasin or the tub can be sucked dry through the shower because of negative pressure or partial vacuum in the supply or feed line. Such fittings or faucets should include safety devices by means of which there is precluded back suction of soiled or contaminated water to the supply o feed line.
A fitting of this type is known from and disclosed to the art in, for example, German Published Patent Application No. 3,603,503, published Aug. 6, 1987. This known mixing faucet with hose-shower outlet comprises a fitting housing mounted at a sink-basin table, in which housing there is arranged a control cartridge actuatable from one side of the housing. This control cartridge is connected at the inlet side thereof with supply or feed lines for hot water and cold water, whereby mixed water leaving the control cartridge arrives at a mixing or discharge chamber arranged within the housing and partially enclosing the control cartridge. Mixed water is then delivered or conducted from the mixing or discharge chamber through an outflow hose to the outlet or spout provided in a hose shower. In the fitting housing there is provided a safety device located below the control cartridge and arranged in flow connection with the mixing or discharge chamber, such safety device being arranged about 3 cm to 5 cm above the highest possible water level in the sink basin and having a ventilation aperture leading out of the fitting. Under normal operating conditions, the ventilation aperture is closed by means of a sealing member. Such sealing member bears upon an annular shoulder or seat bounding the ventilation aperture. When now a negative pressure occurs in the supply or feed line and the control cartridge remains open, the sealing member is lifted off from the annular shoulder or seat, so that the flow path of water is connected with the environment by means of the ventilation aperture. The supply or feed line as well as the outflow hose are thus ventilated, in order to preclude a back-suction of water into the supply or feed line.
In this prior art construction of a mixing faucet with hose-shower outlet there are only relatively slight or small pressure differences available or disposable for lifting off the sealing member from the annular shoulder or seat, in order to ventilate the supply or feed line and the outflow hose under conditions that render possible a backflow. These only slight pressure differences available require an extremely easy-running or high-sensitive construction of the safety device, whereby the operational reliability is particularly made uncertain by furring in the fitting. The required smooth running of the known safety device is moreover a disadvantage in that, upon rapidly cutting off the flow of water when the control cartridge is closed, the sealing member is lifted from the annular shoulder or seat by negative pressure build-up in the outflow hose, so that leaking water can flow out of the fitting through the safety device even under quite normal operating conditions.